At present, a mobile communication system called the third and a half generation has prevailed. An environment has further been improved in which a mobile terminal is connected to the Internet to use an electronic mail and the Web access.
On the other hand, the next generation radio communication service with a broader bandwidth (5 MHz or higher) and a high transmission rate of 10 Mbps or higher has been standardized and developed. The next generation radio communication service is known as the 3.9 generation mobile communication system called worldwide interoperability for microwave access (WiMAX) and long term evolution (LTE) using orthogonal frequency division multiplexing access (OFDMA).
In general, a transmission control protocol (TOP) used as a transport protocol between a mobile terminal and a server system has a retransmission control function using a sequence number (control number) and an acknowledgement. Thereby, the TOP can provide a high reliability communication. The TOP has a rate control function to transmit the next packet in conformity with a timing in which the acknowledgement arrives in order to transmit a packet in conformity with the bandwidth of a network.
In general, the transmission rate of a radio access is network between a mobile terminal and a base station is lower than that of a network between a server system and a wireless access gateway. For this reason, if congestion in which a buffering packet increases is detected in the entity of a link layer in the radio access network, gateway equipment (a node) (or a base station or a wireless access gateway) adjusts the pacing of transmission of an acknowledgement by buffering a packet of the acknowledgement (refer to JP-T-2002-527936, for example).